The invention will now be described further herein, with reference to the accompanying drawings, in which:
Referring now to the figures,
In order to direct light from the POF 150 the reflecting and receiving means 102 has a curved inner surface which is adapted to reflect a large proportion of incident light. The surface may be adapted to reflect light by being polished, metallised or covered with a reflective coating. To improve reflective performance if the surface is polished, the whole reflecting and receiving means 102 may be formed from white material.
The reflecting and receiving means 102 can be mounted on the integrated circuit 101 in any suitable manner. For example, a suitable adhesive material can be used. For additional stability, the reflecting and receiving means 102 may be further shaped so as to make contact with the substrate 109 on one or more sides of the integrated circuit 101. The POF 150, is retained in the open end of the reflecting and receiving means 102 by any suitable means which allows optical coupling of the POF to the moulding 102.
Referring now to
The integrated circuit 101 may also comprise suitable control and or processing circuitry to process signals generated by the light sensing means 104 and to generate signals for output to other devices connected to the integrated circuit 101 via bond pads 107.
In alternative embodiments, the integrated circuit 101 may comprise light emitting means and additional light sensing means, operable to monitor the performance of the light emitting means. Integrated circuits 101 incorporating such additional elements are discussed in more detail later in the specification.
Referring now to
The wafer 201 and the reflecting and receiving means array 202 are separated into individual optical data transceivers by sawing, laser scribing or any other known semiconductor separation techniques or a combination of two or more such techniques. The individual optical data transceivers can then be mounted onto suitable substrates or packaged, as desired or as appropriate. As a result of the separation from the array, the reflecting and receiving means may have side portions 202a, 202b.
In alternative embodiments, the wafer 201 and reflecting and receiving means array 202 can be separated into optical data transceivers incorporating two or more reflecting and receiving means 102 and two or more integrated circuits to form multiple POF interfaces. In a still further embodiment the reflecting and receiving means array 202 can provide a plurality of reflecting and receiving means 102 for a corresponding plurality of light sensing means provided on each integrated circuit 101 to provide a multiple POF interface.
Referring now to
The reflecting and receiving means 302 is operable to direct light emitted by the light emitting means 305 at wide angles into an optical fibre 350 and to direct light proceeding from the end of optical fibre 350 to the first and second light sensing means 306, 304. It is also operable to retain the optical fibre 350 in position relative to the light emitting means 305 and the first and second light sensing means 306, 304. The reflecting and receiving means 302 is mounted on to the integrated circuit 301 by adhesive 315. In order to direct light from the light emitting means 305 into the optical fibre 350, the reflecting and receiving means 302 has a curved inner surface 303 which is adapted to reflect a large proportion of incident light. The surface 303 may be adapted to reflect light by being polished, metallised or covered with a reflective coating. To improve reflective performance if the surface is polished, the whole reflecting and receiving means 302 may be formed from white material.
Referring now to
The optical transceiver is packaged by taking the integrated circuit 301 and attached light emitting means 305, and mounting them on said substrate 309. Before packaging, said reflecting and receiving means 302 is mounted on said integrated circuit 301, said reflecting and receiving means 302 being aligned so as to reflect light from said light emitting means into said optical fibre 350 and to reflect light from said optical fibre onto said light sensing means 306, 304.
Once the reflecting and receiving means 302 is in position, a blob of gel 310 is applied to the optically active elements. The blob of gel 310 may be amorphous or may be shaped so as to form a lens and accentuate the effect of the reflecting and receiving means 302. A potting compound 311 is then dispensed onto the surface of the integrated circuit 301, and substrate 309 so as to cover their upper surfaces except that portion upon which the reflecting and receiving means 302 sits. The potting compound 311 provides protection for all the components of the optical transceiver whilst leaving an opening through which an optical fibre 350 may be inserted to allow light to be directed to said light sensing means 304 and directed away from said light emitting means 305. The potting compound is in a fluid state when applied to the substrates 301, 309 and as such the surface tension of the potting compound before it sets results in the curved ends 312 of the package.
The gel blob provides protection for the optically active elements during and after potting. It is also possible that, the gel blob 310 may be added after potting or may be omitted altogether, if desired. The gel may be any suitable transparent compound such as a transparent epoxy or a silica based gel. The gel blob may be formed to any desired shape by use of any suitable method.
It is of course obvious to the skilled man that such a transceiver 300 may be a transceiver with light emitting means only or with light sensing means only or with both in addition to the embodiment described herein comprising light emitting means 305 and first and second light sensing means 306, 304 for monitoring and controlling the performance of the light emitting means in addition to receiving optical signals.
Often optical data transmission systems use optical fibres 350 terminated by a ferrule. In order to comply with such systems, the packaged transceiver may be adapted to have a ferrule receiving means fitted thereto.
Referring now to
The reflecting and receiving means 402 is operable to direct light emitted by the light emitting means 405 at wide angles into an optical fibre 450 and to direct light proceeding from the end of optical fibre 450 to the first and second light sensing means 406, 404. It is also operable to retain the optical fibre 450 in position relative to the light emitting means 405 and the first and second light sensing means 406, 404. The reflecting and receiving means 402 is mounted on to the integrated circuit 401. by adhesive 415. In order to direct light from the light emitting means 405 into the optical fibre 450, the reflecting and receiving means 402 has a curved inner surface 403 which is adapted to reflect a large proportion of incident light. The surface 403 may be adapted to reflect light by being polished, metallised or covered with a reflective coating. To improve reflective performance if the surface 403 is polished, the whole reflecting and receiving means 402 may be formed from white material.
Referring now to
Once said integrated circuit 401 is mounted on said lead frame, said reflecting and receiving means 402 is mounted on said integrated circuit 401, said reflecting and receiving means being aligned so as to reflect light from said light emitting means into said optical fibre 450 and to reflect light from said optical fibre onto said light sensing means 406, 404.
In an alternative preferred embodiment, said reflecting and receiving means is attached to said integrated circuit whilst said integrated circuit is in wafer form.
Once the reflecting and receiving means 402 is in position, a blob of gel 410 is applied to the optically active elements. The blob of gel 410 may be amorphous or may be shaped so as to form a lens and accentuate the effect of the reflecting and receiving means 402. The integrated circuit 401, lead frame 409 and reflecting and receiving 402 are then placed into the cavity of a moulding tool. The cavity has a projection adapted to be in contact with said reflecting and receiving means 402.
A moulding compound 411 is then introduced into the cavity so as to encapsulate the integrated circuit 401, lead. frame 409 and reflecting and receiving 402 except for the peripheral portions of lead frame 409 and an opening corresponding to the position of the projection above said reflecting and receiving means. The moulding compound 411 provides protection for all the components of the optical transceiver 400 whilst leaving an opening through which an optical fibre 450 may be inserted to allow light to be directed to said light sensing means 404 and directed away from said light emitting means 405.
The gel blob 410 provides protection for the optically active elements during and after encapsulation. It is also possible that, the gel blob 410 may be added after encapsulation if the projection is adapted so as not to damage the optically active elements of the integrated circuit 401 during encapsulation or may even be omitted altogether, if desired. The gel may be any suitable transparent compound such as a transparent epoxy or a silica based gel. The gel blob 410 may be formed to any desired shape by use of any suitable method.
In a further alternative embodiment, it is possible that the reflecting and receiving means is not mounted to said integrated circuit 401 until after encapsulation. In such embodiments, a blob of gel 410 is applied to protect the optically active elements during encapsulation, the projection of the mould tool remaining in contact with the gel blob 410 during encapsulation, thereby providing an opening over said gel blob 410. The reflecting and receiving means 402 is then inserted into and mounted in said opening thus providing a packaged optical transceiver 400 as described above. In such embodiments, it is also possible that, if desired, the gel blob 410 may be omitted, provided that the projection is adapted so as not to damage the optically active elements of the integrated circuit 401 during encapsulation.
The above described methods may also be adapted to include the further step of applying Teflon tape to the unpackaged transceiver in the mould cavity, to cover at least the optically active elements. This provides additional protection for the optically active elements and is known as the Boschman Technique.
It is of course obvious to the skilled man that such a transceiver 400 may be a transceiver with light emitting means only or with light sensing means only or with both in addition to the embodiment described herein comprising light emitting means 405 and first and second light sensing means 406, 404 for monitoring and controlling the performance of the light emitting means in addition to receiving optical signals.
Often optical data transmission systems use optical fibres 450 terminated by a ferrule. In order to comply with such systems, the packaged transceiver may be adapted to have a ferrule receiving means fitted thereto.
It is of course to be understood that the invention is not intended to be restricted to details of the above embodiments which are described by way of example only.
Number | Date | Country | Kind |
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0326106.2 | Nov 2003 | GB | national |
0408653.4 | Apr 2004 | GB | national |
0408660.9 | Apr 2004 | GB | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB04/03674 | 11/10/2004 | WO | 00 | 7/17/2007 |